The present invention relates to piston-type flush valves for toilets and urinals and more specifically to an improvement in the valve seat which both provides a better seal for the piston and provides a fluid passageway between the flush valve inlet and the solenoid-operated fluid piston.
U.S. Pat. Nos. 5,881,993 and 4,261,545, among other patents, all owned by Sloan Valve Company, show piston-operated flush valves for use in flushing toilets and urinals. In each of these patents there is a piston which closes upon a valve seat in the flush valve body. U.S. Pat. No. 6,299,127, also owned by Sloan Valve Company, shows a solenoid-operated, hydraulically-driven piston for tripping the relief valve in a diaphragm-type flush valve and that type of flush valve actuator is used in the presently-disclosed piston operated flush valve. The present invention is specifically directed to an improved valve seat which provides communication between the flush valve inlet and the water passage leading to the solenoid-operated, hydraulically-driven flush valve actuator. The seat further has a new and effective seal between it and the flush valve piston, all of which are directed to a more effective and efficient piston-type flush valve.